This invention generally relates to printing or duplicating machines and, more particularly, to a bracket assembly for receiving and positionally adjusting the shaft end of a form roller in the printing couple of the machine.
Printing machines normally include a printing couple which comprises a number of cylinders and/or rollers such as impression cylinders, master cylinders, blanket cylinders, ductor rollers, transfer rollers, regulator rollers, and the like. For instance, an ink fountain is disposed generally at the rear of the machine for feeding ink to the various rollers of the printing couple which transfers images to copy sheets. In such printing machines as rotary offset lithographic duplicating machines, a moisture fountain also is disposed adjacent the printing couple for feeding moisture to the printing couple. A number of rollers which generally can be termed "distribution" rollers are provided between the ink fountain and/or moisture fountain for distributing ink and/or moisture to the printing couple of the machine.
The distribution rollers conventionally are mounted between spaced side frame plates of the machine framework. Many of the rollers are arranged in triangular arrays, and the rollers define distribution gaps with other adjacent rollers to form flow paths for the ink and/or moisture to the master or plate cylinder. Throughout the complex system of rollers, the "gaps" or pressure between adjacent rollers must be capable of regulation or positional adjustment in order to regulate the flow of ink or moisture through the flow paths of the roller system to the printing couple. The position of the rollers is critical in order to avoid lines or "shadows" on the imaged copy which are caused by uneven distribution of the ink or moisture. For instance, any "play" between the distribution rollers adversely affects the maintenance of proper ink gaps and results in poor copy quality.
Heretofore, roller mounting and adjustment mechanisms have been extremely complicated. Often, the machine must be shut down in order to perform any adjustments. In some instances, one or more of the rollers may have to be removed in order to accomplish any adjustments. This further complicates the construction of the mounting assemblies or brackets for the form rollers.
These problems further are complicated in machines where it may be necessary to separate one or more rollers during down time, such as during overnight periods when the machine is not operating. If two adjacent rollers are maintained in contact during any extended period of time, particularly where the rollers are fabricated of resilient material, set line indentations are created which form lines or shadows on the imaged copy. Therefore, separation or "night latch" mechanisms often are incorporated in the roller system to separate adjacent rollers during down time.
It would be desirable to provide simple, effective and easy to adjust mechanisms and bracket assemblies for positioning the form rollers in a manner to obviate the problems caused by the complex mechanisms described above. This invention is directed to solving the above problems and satisfying such a need for a simple bracket assembly for mounting form rollers in a printing or duplicating machine.